avionics, sensors, and simulation...

Avionics, Sensors, and Simulation

Project

ENAE 483 Fall 2012

Chrissy Doeren

Tom Noyes

Sean Robert

Josh Sloane

Description of Project

• Perform the avionics design for a lunar program crew cabin

• Calculate communications link budgets for the following links

o Ku band direct to Earth

o S band direct to Earth

o Ka band to L2 relay satellite

o Ku relay satellite direct to Earth

o UHF omni to EVA suits

• Compile a sensor list for all systems in the cabin

o Type and number of sensors for each signal

o Criticality of sensor

o Frequency of sampling

Group D10 Avionics, Software, and Simulation

Description of Project

Cont'd • Develop a list of possible Design/Build/Test/Evaluate (DBTE) projects for

ENAE 484 next term

• For each concept, briefly discuss:

o Research objective (what do we learn/why do we care?)

o Required mockup/test apparatus

o Concept of test operations (include simple sketches)

• Rank your top three concepts in priority order, based on importance and

feasibility


Communications Link

Budget Analysis

Communications Link Budget Analysis

Link budget analysis performed using

maximum possible slant distance based on

orbital geometry

• Ku Band Direct to Earth

• S Band Direct to Earth

• Ka Band to L2 Relay Satellite

• Ku Relay Satellite Direct to Earth

• UHF Omni to EVA Suits



All Antennas

Overall System Architecture



All Antennas

Assumptions

• Ku, S, and Ka band antennas are parabolic dishes

• UHF antenna is omnidirectional dipole

• Ku and S band Earth antenna is 34 m diameter

• Deep Space Network (DSN)

• Ka band L2 relay satellite antenna is 0.3 m diameter

• UHF omni antenna is 0.11 m diameter

• Dictated by wavelength of signal



Slant Distances

• Ku and S bands direct to Earth: maximum

transmission distance is orbital radius of the Moon

around the Earth at apogee = 405,410 km

• Ka band to L2 relay satellite: 60,000 km

• Ku band relay satellite direct to Earth: 465,410 km

• UHF omni to EVA suits: 10 km

• Maximum EVA distance by suited astronaut



Ku Band Direct to Earth

Trade Studies – vary antenna size and transmit power

Transmit Antenna

Size

Receive

Antenna Size

Transmit Power Link Margin

0.3 m 34 m 0.04 W 4.01 dB

0.7 m 34 m 0.04 W 11.37 dB

0.3 m 34 m 0.12 W 8.78 dB

0.7 m 34 m 0.12 W 16.14 dB



S Band Direct to Earth


Transmit Antenna

Size

Receive

Antenna Size


0.3 m 34 m 1 W 4.37 dB

0.7 m 34 m 1 W 11.73 dB

0.3 m 34 m 3 W 9.14 dB

0.7 m 34 m 3 W 16.5 dB



Ka Band to L2 Relay Satellite


Transmit Antenna

Size

Receive

Antenna Size


0.3 m 0.3 m 0.5 W 3.78 dB

0.7 m 0.3 m 0.5 W 11.14 dB

0.3 m 0.3 m 1.5 W 8.55 dB

0.7 m 0.3 m 1.5 W 15.91 dB



Ku Band L2 Relay Satellite to Earth


Transmit Antenna

Size

Receive

Antenna Size


0.3 m 34 m 0.05 W 3.78 dB

0.7 m 34 m 0.05 W 11.14 dB

0.3 m 34 m 0.15 W 8.55 dB

0.7 m 34 m 0.15 W 15.91 dB



UHF Omnidirectional to EVA Suits

Trade Studies – vary transmit power

Transmit Antenna

Size

Receive

Antenna Size


0.11 m 0.11 m 0.001 W 4.39 dB

0.11 m 0.11 m 0.005 W 11.38 dB

0.11 m 0.11 m 0.01 W 14.39 dB

0.11 m 0.11 m 0.05 W 21.38 dB



Optimum Configurations

Min acceptable link margin = 3.0 dB (2x Factor of Safety)

Link Transmit

Antenna Size

Receive

Antenna Size

Transmit

Power

Link Margin

Ku Band Direct to

Earth 0.3 m 34 m 0.04 W 4.01 dB

S Band Direct to

Earth 0.3 m 34 m 1 W 4.37 dB

Ka Band to L2

Relay Satellite 0.3 m 0.3 m 0.5 W 3.78 dB

Ku Band L2 Relay

Satellite to Earth 0.3 m 34 m 0.05 W 3.78 dB

UHF Omni to EVA

Suits 0.11 m 0.11 m 0.001 W 4.39 dB


Sensors

Proprioceptive Sensors

• Measure internal state of system

o Position, velocity, acceleration sensors: low criticality, high sampling

rate

o Temperature, CO2, acoustic sensors: high criticality, low sampling rate

• Rotary position

• Linear position

• Velocity

• Accelerations

• Temperature

• CO2 sensor

• Acoustic sensor


Linear and Rotary

Sensors • Rotary position [1]

o Provide an output signal that is proportional to

rotation. The sensors have a very fast start

up from power on and provide an almost

instantaneous signal

o Output calibrated to angles between 20

and 160 degrees

o Low-cost and compact

• Linear position [1]

o Provide a linear output characteristic with

displacement which can be proportional to

the supply voltage

o Compact, accurate, robust and don't need special sensitive magnetic

components or magnets which attract debris

o Used for high temperature applications, rugged, stand alone


Velocity and

Acceleration Sensors • Velocity [2]

o Structured to accommodate the rigorous configuration control

demands of aerospace applications

o Have survived testing of: high vibration, shock, extremes of

temperature,salts, acids, solvents and fuels

• Accelerometer [3]

o Detects level of achieved

acceleration for each phase of the

mission

o -65º to 250ºF


Temperature, CO2, and

acoustic Sensors • Temperature [5]

o Extreme temperature Hall sensor, magnetic-sensitive semiconductor

structure is built-in

o -270º to +300º C

• CO2

o Placed inside crew cabin, connected to instrumentation panel

o Low sampling rate, will trigger an alarm if levels start climbing; CO2

scrubbers may need attention

• Acoustic [4]

o Detects small meteorite impacts in earth orbit

o When a collision occurs in space, it makes a rather loud sound,

generating an acoustic wave in a wall that can be detected tens of feet

away by sensors on the walls

o Stamp-size devices, made with a very sensitive piezoelectric material


Sensor Placement

• Collision (acoustic) sensors on bottom, where most collisions occur

• Accelerations spread out covering as much area as possible


Avionics Architecture

Displays and Controls

Block Diagram


Design/Build/Test/Evaluate

Concepts

• Research objectives

o Determine lines of sight for the pilot while landing the vehicle

• Required mockup/test apparatus

o Mockup of exterior of the cabin including:

Landing gear

Windows

o Interior of the cabin including

Pilot seat

Navigation display and controls

o Constructed out of

Wood and/or cardboard

Structural integrity unimportant, except for the floor of the crew

cabin

1. Line of Sight Mockup


•

• Concept of test operation

o Pilot will perform representative operations needed during landing on

the moon

o Analyze:

Comfort of looking out of the window while operating navigation

devices

Position of avionic equipment

1. Line of Sight Mockup

(Cont'd)


1. Line of Sight

Mockup: Sketch



o Determine appropriate locations of cameras

o Cameras needed for:

Additional visibility for landing gear

Monitor pilot's eyes/face to make sure he/she is focused

Camera with the same line of sight as the pilot, so ground support

can see what the pilot sees

Docking


o Similar mockup from line of sight concept

o Several cameras/video cameras with different lenses (e.g. wide angle)


o Take images at different positions

o Determine if these images provide useful information to the pilot and

ground support

2. Video Camera

Locations


2. Video Camera

Locations: Sketch



o Construct a small scale model of our design

o Bring this mockup to grade school classrooms, as a method of

outreach

o Model should be interactive and entertaining for students

Doors should open and close

Landing gear should be able to fold in at its hinges


o Model should be fairly rigid, possibly made out of plastic using a rapid

prototyping machine


o A physical model will help the systems design understand what is still

needed, and how everything works together

o This model could communicate or overall design (especially to non-

engineers) more effectively

3. Small scale model of

design



o Analyze ingress and egress of the lunar lander

o Determine ladder location and spacing of the steps on the ladder to

get to the ground


o Neutral buoyancy lab

o PVC pipe mockup of the cabin

o PVC pipe ladder


o Diver will perform ingress and egress of the vehicle in neutral

buoyancy lab

o Diver will wear the proper amount of weights to simulate moon gravity

4. Neutral Buoyancy

Lab



o Determine feasibility of habitation of crew capsule over long durations

o Construct a full-scale, partially functioning model of our concept.


o Mockup interior of the cabin including

Bedding

Functional food and water systems

Functional ventilation system

Functional waste disposal system


o Three 95th percentile classmates live in the capsule for multiple

consecutive days, performing representative tasks and determining

habitability of capsule.

5. Cabin Life


• Line of sight mockup

• Neutral buoyancy lab

• Cabin life

• All three of these concepts are feasible for the scope of our project

• These all test human factors that would be difficult to analyze with only

CAD drawings

Top 3 Concepts,

In Order of Priority


• [1] http://www.positek.com/Overviews/p503oview.htm

• [2] http://www.smith-systems-inc.com/products

• [3] http://www.select-controls.com/acceleration.html

• [4] http://www.space.com/11856-spacecraft-sensors-sound-collisions.html

• [5] "Hall Effect Magnetic Field Sensors for High Temperatures and Harmful

Radiation Environments." Hall Effect Magnetic Field Sensors for High

Temperatures and Harmful Radiation Environments. Physorg, 22 Mar.

2012. Web. 11 Dec. 2012.

References


avionics, sensors, and simulation...

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